i have a davis vantage vue with a and win 10. the batteries went in the station console it was acouple of days before i change batteries when on start of progam i get error 32701 up and till this point it had not miss a beat even changed batteries before.
just disconnected usb and computer does not recognise it and i found kaspersky and quarantine cumulus thought it was a trojan

I am getting this error with my Vantage Pro 2 on Win 8 - the configuration has been stable for a couple of years, but today after a PC re-boot Cumulus won't communicate with the Vantage Pro station and gives error -32701 regardless of the com port setting (was port 4, and looking in Device Manager on the PC, com port 4 is the only one that appears to be in use - listed as Silicon Labs CP210x USB to UART Bridge (COM4).

Further info...when I try running WeatherLink to test the USB comms under settings/Communications Port, I get "error communicating through USB". If I select "Serial" and auto detect, mostly it fails to find a station, but occasionally finds the Vantage Pro. Of course, when switching back to Cumulus, it mostly fails to find it again...but occasionally does. Most peculiar.

When I have had error 32701 it was usually because I had Weatherlink already running when starting Cumulus. To get a connection again I would stop Cumulus (make sure Cumulus is not running) start Weatherlink, confirm the WL settings/Com port, etc. and after Weatherlink got connected then close it and start Cumulus. You must make sure that Weatherlink is set up and running as Serial and not USB. I think there is a FAQ on 32701 and several past discussion on the forum.

I've got this same problem, caused by essentially the same action, but I can't figure out how to install and run Weatherlink. It appears that they've changed everything about their website. I've tried every COM port from 1 to 4 - are there more? Do I need to restart my computer each time I change the port number? HELP!

Yes there can be more than com 4, my Weatherlink Davis datalogger is com 4 (use this in Cumulus settings) and my sunrecorder is com 6.
You shouldn't need to restart the computer each time you change but rebooting often clears things up.

You install Weatherlink program from the CD that comes with the Davis datalogger. It is not a necessity to run Weatherlink program for using Cumulus (you can't run both at the same time unless you have Virtual VP running), but it is a good indicator if you have correct settings. Weatherlink program has a Test for communication and that helps for getting that correct.

I just had a 32701 error in Cumulus and a Communication error in Weatherlink yesterday when I was testing both with Virtual VP. Stopping both Weatherlink and Cumulus, then restarting them both with the correct settings solved that and now both are working.

Possibly related...but I am finding that on restarting Cumulus after it has been offline for a while (power cuts, etc.) that it no longer reads logged info from my Vantage Pro 2, so I get gaps in the data when that happens. Used to be fine. Is this a known problem?

I would say no it is not.
I know one of the issues discussed in this thread was human mistake and now working fine.

Are you uploading to Weather Underground and have you set the Catch Up, and if so is the catch up sent to WU?

I would suggest that when you have an issue you start from a clean computer reboot (making sure to correctly stop Cumulus):
check your physical connections, i.e. console/Envoy is receiving, datalogger plugged in tightly and in the correct place;
run Weatherlink to see if it is working using serial mode and the correct com port, and that it is downloading from the data logger (browse station data);
stop Weatherlink and run Cumulus;
make sure Cumulus settings are serial and correct com port.
In other words, double check everything!!

In your case of not downloading from data logger, that may be a different issue and turning on Debug log and look in there to see if any indication of what problems encountered.

Not sure if I am totally up to date as to what is or isn't working for you now. Can you again list your current issue(s). Also any link to your WU station, and any webpage?

Again, I am far from knowledgeable but this post disturbs me:

Further info...when I try running WeatherLink to test the USB comms under settings/Communications Port, I get "error communicating through USB". If I select "Serial" and auto detect, mostly it fails to find a station, but occasionally finds the Vantage Pro. Of course, when switch...

If you run Weatherlink in USB mode and then want to run in serial, as you must to use Cumulus or any other third-party program, then you need to first run a utility from Davis to get it in serial mode. Could this be an issue?

Regarding WU catch up, from what I understand there is no communication from the station to Cumulus so Cumulus wouldn't be able to send data to WU but as per the usual diagnostic steps, tick the Debug Log and FTP Logging in Cumulus Settings and leaving it checked for a few minutes and then look in the log files and see if there is anything there that could give a clue.

Progress on one front at least. I had a UPS attached to the PC that was running Cumulus, and the UPS monitoring software appeared to be interfering with Cumulus's access to the USB ports...having disabled the monitoring software Cumulus now reliably connects to the Vantage Pro over the serial link. However, still not entirely right, because catchup still seems to be an issue if Cumulus goes offline for a while - the intervening data doesn't appear in either WU or the Cumulus database. Haven't had a chance to examine the debug logs yet though.